Recently, a variety of researches have been made for a terminal for providing a continuous service during handover. To this end, a media-independent handover has been suggested in IEEE 802.21, so that a standardization activity is being done to perform handover initialization, handover preparation and handover execution independently of media. Especially, there are increasing demands for detecting and selecting a currently available network before a handover is performed. To meet the demands, a lot of researches have been made to develop a handover management scheme in which a handover is decided based on more flexible criteria rather than merely based on signal strength.
In a policy-oriented research, there has been proposed a method of creating an appropriate handover plan through the use of a cost function. Also, a method of modeling a handover using a hypertext transport protocol (HTTP) traffic has been suggested. Moreover, there has been presented a method of deciding a vertical handover depending on a service cost, security, a required power amount, a user's preference, a service quality and a speed. However, such methods do not show in a sufficient detail how such values should be evaluated and applied. Further, researches have been made on a model of performing an intelligent handover directed to a best network interface at a best time. However, most of the researches provide no more than abstract directions, but do not show specified parameters and computing methods.